Internal-combustion engine



Jan. 25, 1949. H. o. HEDGES INTERNAL-COMBUSTION ENGINE 2 Sheets-Sheet 1 Filed June 26, 1945 fndentor HARRY o. HEDGES B J Jan. 25, 1949. H. o. HEDGES 2,460,257

INTERNAL-COMBUSTION ENGINE Filed June. 26, 1945 2 Shets-Sheet 2 i filing Indenbor a HARRBY 0W3 if a $20 a2;

Patented Jan. 25, 1949 INTERNAL-COMBUSTION ENGINE Harry 0. Hedges, Philadelphia, Pa., assignor to Hedges Motor Company, Seattle, Wash., a corporation of Washington Application June 26, 1945, Serial No. 601,585

8 Claims.

This invention relates generally to internal combustion engines and more particularly to improvements in the construction and design of such engines having a reciprocating piston operative in conjunction with a double acting cylinder.

Among the principal objects of the present invention is to provide a small stationary or portable engine designed for operation on the two stroke cycle principle and in which use of the conventional exhaust valves is eliminated, the exhaust gases being discharged by way of an exhaust port provided in the lateral wall of the piston cylinder.

Still another object of this invention is to provide a double-acting piston having at one end thereof a firing head and at its opposite end a compression-suction head, the piston including within itself a spring-pressed valve for controlling the passage of the fuel into the firing chamber of the piston cylinder.

A further object is to provide for air-cooling of the piston to which end the latter is internally provided with bai'fling means for directing the cooling air to traverse the firing head end portion thereof and so insure maximum cooling of the piston, during operation of the engine.

Still another object of the present invention is to provide a construction of engine in which the number of moving parts, such as valves and the like, is reduced to a minimum and wherein the fuel-receiving end of the piston cylinder serves alternately as a suction and a compression chamber during operation of the engine, the fuel being delivered thereto by way of a single intake valve which is adapted for either mechanical or automatic operation.

Other objects and advantages of the invention, such as reside in details of construction and operation of the improved internal combustion engine, will appear more fully hereinafter, it being understood that the present invention consists in the combination, construction, location and relative arrangement of parts, all as described more fully hereinafter, as shown in the accompanying drawings and as finally pointed out in the appended claims.

In the accompanying drawings, which illustrate a preferred construction of the present invention,

Figure 1 is a view partly in vertical section and partly in side elevation of an engine constructed in accordance with and embodying the principles of the present invention;

Figure 2 is a vertical sectional view of the piston employed in the engine;

Figure 3 is a transverse sectional view of the piston taken on the line 3-3 of Figure 2;

Figure 4 is a transverse sectional view taken on the line 4-4 of Figure 2;

Figure 5 is a vertical sectional view of a part of the engine taken on the line 5-5 of Figure 3;

Figure 6 is a vertical sectional view of a part of the engine taken on the line 8-6 of Figure 3;

and

Figure 7 is a transverse sectional view illustrative of details of construction of the piston.

Referring now to the drawings, it will be observed that the engine of the present invention includes a power cylinder ID, the axial line of which is arranged perpendicularly to the axial line of the crank shaft II. This cylinder is rigidly supported upon a base member i2 which is secured to and forms part of the crank case l3, this base member having a wall I! which serves to close the lower end of the cylinder and at the same time being provided with suitable means for guiding the piston rod i5 to which is imparted the necessary reciprocating action by the connecting rod l6 operatively connected to the crank shaft. The piston rod reclprocates through a suitable stufling box, generally designated l'l, provided in the wall l4 of the cylinder supporting member l2, it being understood that the arrangement shown for effecting reciprocation of the piston rod forms no part of the present invention.

However, it may be stated here that various arrangements may be employed in guideways for guiding the travel of the piston rod and for sustaining the lateral thrust of the connecting rod occasioned by the rotary motion of the crank shaft. In the arrangement illustrated, the crosshead embodies rollers is arranged to track between parallel guideways 19.

The upper end of the power cylinder I0 is provided with a closed end wall 20 in which is fitted a fuel ignition device, such as the spark plug 2|, while the cylindrical wall of the cylinder is externally provided with annular heat radiating fins 22. Provided at the lower end of the power cylinder in the immediate region of its supporting base member I2 is the fuel intake passage 23 the inlet port to which extends laterally of the base member, as indicated at 24. The fuel flow into and through the passage 23 is controlled by a springpressed valve 25, the stem 26 of which is slidably fitted within a guide 21 therefor formed in the base member I2. This stem 26 is embraced by a compression spring 28 biased to normally maintain the valve seated in its closed position as shown in Figure 1. Any suitable actuating mechcrank shaft to alternately open and close the intake valve 25, opening of the latter being efl'ected by the arm 23 pushing upwardly on the valve stem 26 against the resistance of the compression spring 23.

The power cylinder I is further provided in the wall thereof at a suitable point between its opposite ends with a lateral exhaust port 3| having free communication between the firing chamber of the cylinder and atmosphere. In addition to this exhaust port 3|, the power cylinder 2 is provided in the side wall thereof at diametrically opposite points with a pair of air cooling ports, the port 32 being the inlet for the cooling air and the port 33 the outlet therefor, the ports 32 and 33 being designed to permit the free circulation of cooling air through the piston in the manner presently to appear.

Fitted within the power cylinder for reciprocation therein is a piston 34 the cylindrical walls of which are open at diametrically opposite sides, as at 35 and 36. Opposite ends of the piston are respectively provided with circumferentially continuous wall or skirt portions 3'! and 38, the inner edges 39 and 48 of which de fine the opposite limits of the side wall openlugs 35 and 36.

Formed as an integral part of the piston interiorly thereof is a generally tubular passageway the upper end of which terminates in a valve seat 42 which is adapted to be engaged by a spring-pressed valve 43. The stem 44 of this valve is guided for vertical movement within a support 45 centrally formed within the passage 4| as an integral part thereof, the stem having imparted thereto a normal downward bias by the compression spring 45 which embraces the stem with its opposite ends respectively abutting the stem guide 45 and an abutment 46 carried by the valve stem. The lower end of the passage 4| is in free communication with the fuel intake passage 23, while the upper end thereof communicates with the firing chamber of the cylinder when the valve 43 is open, as shown in Figures 1 and 5.

The circumferentially continuous end wall portions of the piston, at opposite ends thereof, are in each case fitted with conventional piston rings 41. The interior of the skirted portion of the piston at the firing end thereof is provided with a plurality of baflies 48 which extend in spaced parallel relation across the piston from one side wall thereof to the other. In addition, the piston is interiorly provided with a baiile 49 extending substantially at right angles to the upper series of bailies 48, the said baflle 49 being disposed generally in the diametric plane of the piston and between the side wall openings thereof. The upper edge of the baille 49 preferably interconnects with the lower free edges of the bafiles 48 so as to direct cooling air entering through one side wall opening of the pistonupwardly through the spaces between said baffles 48 and thence outwardly by way of the opposite side wall opening of the piston.

The lower end of the baffle 49 is shaped, as at 50, to avoid interference with the internally threaded boss with which is threadedly engaged the upper end of the piston rod IS.

The external surface of the firing end of the piston is provided with a baffle 32 of generally arcuate shape which marginally surrounds a substantial portion of the valve seat 42 and its associated valve 43 to most efllciently direct the course of the incoming fuel delivered into the firing chamber of the power cylinder and so provide for maximum scavenging of the burnt gases and refilling of the combustion chamber.

In operation of the engine, assuming the parts thereof to be in their respective positions shown in the drawings, fuel will have been delivered into the fuel intake chamber 23, the fuel inlet valve 25 will have been closed as shown and the piston 34 will have been forced downwardly into its lowermost position by the explosion and expansion of the gas fuel in the fuel combustion chamber following ignition thereof by the spark plug 2|. In this position of the piston 34, the intaken fuel in the intake chamber 23 will be compressed and forced upwardly through the passage 4| into the upper combustion chamber of the cylinder, the pressure of the fuel so passing through the passage 4| being sufilcient to unseat the valve 43 against the resistance of the spring 45.

On the upward fuel compression stroke of the piston, the fuel thus delivered into the upper combustion chamber of the cylinder is compressed therein simultaneously as a suction is created in the fuel intake passage 4|, resulting in closing of the valve 43 under the combined effect of the pressure exerted upon the valve head and the effort of the spring 45, the intake valve 25 being then opened. Upon compression of the fuel in the upper head of the cylinder, ignition thereof is effected by the spark plug resulting in explosion and expansion of the fuel to force the piston downwardly in the performance of its power stroke. Simultaneously as the piston is so forced downwardly along its power stroke, the fuel intake valve 25 is closed, in consequence of which the fuel in the intake chamber 23 is compressed by the descending piston, the pressure of the expanded gases in the firing chamber being sufficient to maintain the valve 43 closed until the instant of exhaust of the fired gases by way of the exhaust port 3| (see Figure 6). Exhaust occurs when the piston closely approaches the lower limit of its downward stroke, at which time the upper end of the piston will have passed below and so opened the port 3| to free exhaust of the exploded gases from the firing chamber of the cylinder.

When the exhaust port 3| is thus uncovered by the piston, the pressure in the upper combustion chamber immediately drops with the result that the pressure of the fuel in the intake chamber and the passage 4| becomes operative to open the valve 43 and so permit a new charge of fuel to be introduced into the upper combustion chamber. As the piston commences on its upward fuel compression stroke, the intake valve is opened allowing a further charge of fuel to be drawn by suction into the intake passage 23.

The charge of fuel thus introduced into the firing chamber is so deflected by the arcuate baflle 52 as to most effectively distribute it throughout the chamber and so provide for the evacuation therefrom of all burned fuel and gases upon exhaust thereof through the lateral port 3 I. The same cycle of operation is, of course, continuously repeated. By means of the air cooling ports 32 and 33 formed in the cylinder wall which are respectively in constant communication with the side wall openings 35 and 33 of the piston during all positions of the latter, cooling air is cient cooling, the baflie 40 so operates in conlunction with the baffles 48 as to direct the cooling air across the top internal portion of the piston and thus through the region subject to the greatest degree of heat. The path of the cooling air through the piston is shown in Figures and 6 by the arrows. Thus it is possible to keep the piston satisfactorily cooled for most effective operation 'of the engine,

' What is claimed as new and useful is:

1. In an internal combustion engine, in combination, a cylinder having a fuel intake chamber atone end, fuel ignition means at its opposite end thereof and a port for exhaustion of burned charges located in the wall of the cylinder intermediate its opposite ends, a hollow piston having oppositely closed ends reciprocally operative in said cylinder to compress the fuel charge in the ignition end of the cylinder preliminary to explosion thereof while maintaining said exhaust port closed; and means self-contained in said piston to control the delivery of successive fuel charges into said ignition end of the cylinder by way of a single passage extending through said piston from one closed end thereof to the other, said means including a self-operating springloaded valve operative to close said passage during the compression stroke of the piston toward the ignition end of the cylinder.

2. In an internal combustion engine, in combination, a cylinder having a fuel intake chamber at one end, fuel ignition means atits opposite end thereof and a port for exhaustion of burned charges located in the wall of the cylinder intermediate its opposite ends, a hollow piston having closed opposite ends reciprocally operativein said cylinder to compress the fuel charge in the ignition end of the cylinder preliminary to explosion thereof while maintaining said exhaust port closed, and a self-operated spring-loaded valve mechanism self-contained in said piston to control the delivery of successive fuel charges into said ignition end of the cylinder by way of a single passage extending through said piston from one closed end thereof to the other, said passage being disposed eccentrically with respect to the piston axis of reciprocation and with the wall of said passage substantially tangential with that of the piston.

3. In an internal combustion engine, in combination, a cylinder having a fuel intake passage at one end, fuel ignition means at its opposite end thereof and a port for exhaustion of burned charges located in the wall of the cylinder intermediate its opposite ends, a piston having closed opposite ends reciprocally operative in said cylinder to compress the fuel charge in the ignition end of the cylinder preliminary to explosion thereof while maintaining said exhaust port closed, a piston rod secured to one closed end of the piston and operatively connected to a crankshaft for actuation of said piston, and means self-contained in said piston to control the delivery of successive fuel charges into said ignition end of the cylinder by way of a single passage extending through said piston from end to end thereof, said means including a spring-pressed valve shiftable in the direction of the piston axis to open the passage through the piston upon com pletion of the power stroke thereof.

4. In an internal combustion engine in combination, a cylinder having a fuel intake chamber at one end and a fuel explosion chamber at the other end thereof, said cylinder having a port for exhaustion of the exploded fuel located in the wall thereof at a. point intermediate its opposite ends, a hollow piston having oppositely closed ends reciprocally operative in said cylinder one closed end of said piston being adapted to compress the fuel in the explosion chamber preliminary to explosion thereof and the other end thereof being adapted alternately to subject said fuel intake chamber to compression and suction, a self-op erating spring-loaded valve in said piston for controlling the delivery of successive fuel charges into said explosion chamber by way of a fuel delivery passage extending through said piston between the opposite ends thereof, a fuel inlet port communicating with said intake chamber, and valve means in said port operative to close ed the supply of fuelto said intakechamber during movement of the piston compressing fuel in said intake chamber.

5. In an internal combustion engine, in combination, a cylinder having an explosion chamber at one end thereof and a fuel intake chamber at its opposite end, said cylinder alsohaving diametrically opposed air inlet and exhaust ports in its side walls located at points intermediate its opposite ends, and a hollow piston reciprocally operative in said cylinder, said piston being closed at its opposite ends and having a passage extending transversely therethrough with .its opposite extremities respectively in 'registry with said ports, said passage being of such dimension relatively to said ports as to provide for continuous circulation of cooling air through said piston during all operative positions thereof, the head of the piston adjacent the explosion chamber of the cylinder being internally provided with a series of spaced parallel baffles extending crosswise of the piston, and baffling means within the hollow 40 interior of the piston for directing the cooling air cross-wise of the piston between said parallel bafies.

6. In a two cycle engine, in combination, a closed cylinder having an explosion chamber at one end 'thereof and a fuel intake chamber at its opposite end, said cylinder also having diametrically opposed air inlet and exhaust ports in the wall thereof, a hollow piston reciprocally operative in said cylinder, said piston having oppositely closed heads, an internal baffle within said hollow piston extending diametrically thereof with the one end of said baffle contiguous to the head of the piston adjoining the fuel intake chamber of the cylinder and the opposite end of said bafiie spaced from the head of the piston adjoining the explosion chamber of the cylinder, the wall segments of said piston to either side of said internal baffle having openings therein for respective registry with said air inlet and exhaust ports in the wall of the cylinder.

7. In a two cycle engine as defined in claim 6 wherein the head of the piston adjacent the explosion chamber of the cylinder is internally provided with a series of spaced parallel baffles extending cross-wise of and contiguous to the diametrically extending baille aforesaid.

8. In a two-cycle engine of the character described, in combination, a closed cylinder having an explosion chamber at one end and a fuel intake chamber at the opposite end thereof, a hollow piston reciprocable within said cylinder, said piston being closed at its opposite ends and having a passage extending therethrough from one end to the other thereof for the successive delivery of fuel charges from said intake chamber said cylinder.

HARRY O. HEDGIS.

' l4 0E8 CITED 8 tmmm s'rs'rss PA 'IENT8 Number The following references are oi record in the 15 Number me 01' this patent:

Name Date Merry Mar. 10, 1897 St. John Sept. 24, 1901 Steely Feb. 16, 1909 Sullivan Dec. 10, 1918 De Aburto July 22, 1919 Holmquest Mar. 8, 1921 Cooke Jan. 17, 1922 Knudsen Oct. 18, 1923 Grayson Oct. 16, 1928 Palmer Dec. 25, 1928 FOREIGN PATENTS Country Date France of 1907 

